Immediate Changes in Peripapillary Retinal Vasculature after Intraocular Pressure Elevation -an Optical Coherence Tomography Angiography Study

ABSTRACT

Purpose: To investigate changes in peripapillary retinal vessel density after acute intraocular pressure (IOP) elevation caused by laser peripheral iridotomy (LPI) in primary angle-closure suspects (PACS) by optical coherence tomography angiography (OCTA).

Materials and Methods: Ninety-seven participants with PACS were included in this cross-sectional observational study. OCTA and IOP measurement were performed at baseline and 1 h after LPI. PACS eyes were further divided into three groups according to IOP increase 1 h after LPI (group 1 = IOP elevation <5 mmHg, 42eyes; group 2 = IOP elevation ≥5 mmHg and <10 mmHg, 34 eyes; group 3 = IOP elevation ≥10 mmHg, 21eyes). The changes of vessel density in radial peripapillary capillary (RPC) and entire retina were compared among groups.

Results: When all eyes were included, the vessel density of RPC and entire retina 1 h after LPI were significantly decreased compared to the baseline (RPC: 64.5 ± 7.9 vs.67.8 ± 6.8, P < .001; retina: 86.3 ± 4.6 vs.88.3 ± 3.8, P < .001). There were significant differences among the three groups in the RPC and retinal vessel density at 1 h after LPI (RPC: 67.4 ± 7.3 vs. 63.2 ± 7.6 vs. 60.9 ± 7.5, P = .003; retinal: 87.7 ± 4.0 vs. 85.8 ± 4.5 vs. 84.3 ± 5.2, P = .015). In group 2 with an increased IOP from 5 mmHg to 10 mmHg, the reduction of vessel density in the RPC was more significant than that of the entire retina (RPC vs. retina: 7.1 ± 10.0% vs. 3.0 ± 4.4%, P = .006).

Conclusions: LPI-induced IOP spikes resulted in a decrease in retina vessel density with PACS eyes by OCTA. The reduction of RPC vessel density was more significant than that of the entire retina in the subgroup of IOP increase from 5 to 10 mmHg. This suggests that vessel density in RPC was more sensitive to IOP increase than that of the entire retina in the peripapillary area.

KEYWORDS:

• Peripapillary vessel density
• intraocular pressure
• optical coherence tomography angiography
• radial peripapillary capillary
• laser peripheral iridotomy

Declaration of interest statement

The authors report no conflicts of interest. The authors alone are responsible for the contest and writing of the paper.

Supplementary material

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Additional information

Funding

This study was funded by the State Key Program of National Natural Science Foundation of China [81430007], the subject of major projects of National Natural Science Foundation of China [81790641], National Natural Science Foundation of China [81870661], the Shanghai Committee of Science and Technology, China [17410712500], and the top priority of clinical medicine center of Shanghai [2017ZZ01020]. The sponsor or funding organization had no role in the design or conduct of this research.